What is a cold sore?
Cold sores, also known as fever blisters, are tiny, clear, fluid-filled blisters that form around the mouth and are caused by the herpes simplex virus (usually type 1, or HSV-1) living inside your nerve tissue. Cold sores usually do not last longer than two weeks. However, the sores are highly contagious and tend to recur when the virus is reactivated by a trigger such as stress, sunlight, fever or illness.
What happens when I’m exposed to the cold sore virus (HSV-1)?
Most people get HSV-1 infections during infancy or childhood and usually catch the virus from an infected family member or friend. Only an estimated 30 percent of those infected actually develop the characteristic blisters. If sores do develop, they can appear anywhere from two to 12 days after exposure to an infected person. Other persons with a primary infection may have flu-like symptoms such as a high fever, sore throat, swollen neck glands and mouth soreness.
What are the stages of a cold sore?
Day 1: Prodrome (tingle) stage – Before a cold sore has formed, you may feel a tingling, itching or burning sensation beneath the skin, usually around the mouth or the base of the nose. Applying antiviral medications during this stage can help alleviate cold-sore symptoms.
Days 2 to 3: Blister stage – An outbreak of fluid-filled blisters is the first visible sign of cold-sore formation.
Day 4: Ulcer or weeping stage – Typically, the most contagious and painful stage of cold sores is when blisters rupture, leaving a shallow, reddish, open sore.
Days 5 to 8: Crusting stage – After a few days, the blisters dry up and form a yellow or brownish crust, which eventually falls off. During this stage, it is important to care for the scab, which can crack or break.
Days 9 to 12: Healing stage – Usually a series of scabs will form on the lesion, which eventually flake off. Each new scab will be smaller than the previous one, until the cold sore heals completely, usually without scarring.
